#include<stdio.h>
int main(void)
{
	double term, result = 1;
	for (int n = 2; n <= 100; n = n + 2)
	{
		term = (double)(n * n) / ((n - 1) * (n + 1));
		result = result * term;
	}
	printf("result=%f\n", 2 * result);
	return 0;
}